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0
votes
0answers
83 views

norms of compressible and incompressible vector

Let $a$ be a vector in $R^m$, such that $\sum_{i=1}^ma_i=0$ I would like to bound $\sqrt{2m(2m-1)}\|a\|_{\infty}$ by $\sqrt{2m}\|a\|_2$ (or other way arround with the sharp constants), in the case ...
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0answers
69 views

The notion of approximately sparse vectors in compressed sensing

An x in $\mathbb{R}^n$ is said to be sparse if many of it's coefficients are zeroes. x is said to be compressible(approximately sparse) if many of its coefficients are close to zero.This is how it is ...
9
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0answers
198 views

Complexity of finding the leading eigenvector of a graph Laplacian

Let ${\bf L}$ be the $n\times n$ Laplacian of a graph. What is the worst case complexity for calculating the maximum eigeinvector of ${\bf L}$? Are there any families of Laplacians for which it takes ...
17
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1answer
273 views

complexity of checking if a subspace is a Euclidean section of L1

If $X$ is a linear subspace of ${\mathbb R}^n$, $X$ is high-dimensional, and for every $x\in X$ we have $(1-\epsilon) \sqrt n ||x||_2 \leq ||x||_1 \leq \sqrt n ||x||_2$ for some small $\epsilon ...
1
vote
2answers
250 views

Complexity of Smoothed $\ell_0$ algorithm

I wanted to compute the complexity of a smoothed $\ell_0$ algorithm in BigO notation. The algorithm can be found here. Can anybody help me in this regard?
17
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7answers
996 views

Analogs of compressed sensing

In compressed sensing, the goal is to find linear compression schemes for huge input signals that are known to have a sparse representation, so that the input signal can be recovered efficiently from ...